PS4 - transfer single save?

I'm afraid I might be out of luck here, but wanted to see if there was anything I could do about this!

I brought my physical game to a friend's house and started a new game on their console. I transferred the save file to usb and brought it home after the weekend I spent there. I wanted to put it into my console, but don't want to overwrite the save that currently exists on my home console.

Is there no way to save a single save slot to usb and add it into an existing game (as a second save)?

Thanks!